ColumnMetrics: reset state only if new columns differ from previous

Author: andreypopp

lib/ColumnMetrics.js

@@ -112,7 +112,9 @@ var Mixin = {
   },
 
   componentWillReceiveProps(nextProps) {
-    this.setState(this.getColumnMetrics(nextProps));
+    if (!sameColumns(this.props.columns, nextProps.columns)) {
+      this.setState(this.getColumnMetrics(nextProps));
+    }
   },
 
   getColumnMetrics(props, initial) {
@@ -138,4 +140,34 @@ var Mixin = {
   }
 };
 
+function sameColumns(prevColumns, nextColumns) {
+  var i, len, column;
+  var prevColumnsByKey = {};
+  var nextColumnsByKey = {};
+
+  for (i = 0, len = prevColumns.length; i < len; i++) {
+    column = prevColumns[i];
+    prevColumnsByKey[column.key] = column;
+  }
+
+  for (i = 0, len = nextColumns.length; i < len; i++) {
+    column = nextColumns[i];
+    nextColumnsByKey[column.key] = column;
+    var prevColumn = prevColumnsByKey[column.key];
+    if (prevColumn === undefined || prevColumn.width !== column.width) {
+      return false;
+    }
+  }
+
+  for (i = 0, len = prevColumns.length; i < len; i++) {
+    column = prevColumns[i];
+    var nextColumn = nextColumnsByKey[column.key];
+    if (nextColumn === undefined || nextColumn.width !== column.width) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 module.exports = {Mixin, calculate, resizeColumn};